❃ Pachycephalosaurus was a genus of pachycephalosaurid dinosaur that lived during the Late Cretaceous Period, about 74-65 million years ago. It was one of the last surviving members of its family, and is known for its thick skull roof bones.
❃ This herbivorous dinosaur was roughly 4.5 meters (15 ft) in length, and weighed an estimated 1-2 metric tons (1.1-2.2 short tons). Its skull was up to 30 cm (12 in) thick, and its most distinctive feature was the large domed area at the back of its head. This bone helped protect the brain during fights, and may have also been used to attract mates.
❃ Pachycephalosaurus is known from over 50 specimens, making it one of the best-represented dinosaurs from the Cretaceous Period. It was first described by Edward Drinker Cope in 1871, and its name means "thick-headed lizard". Despite being one of the better-known dinosaurs, much about its life and behavior remains a mystery.